Electroslag welding uses electrical current to produce a molten slag pool from a powdered flux. The molten slag pool melts a filler metal as it is fed into the molten slag. The electrical resistivity of the molten slag provides sufficient heat to continuously melt the filler metal as it is fed into the molten slag pool. During electroslag welding, the molten slag "floats" on the metal to provide a barrier that limits oxidation of the molten filler metal.
Electroslag welding has been used for several years to deposit high quality weld metal at high deposition rates. Materials such as low-carbon steels, medium-carbon steel, low alloy steel, stainless steels and nickel-based alloys have been welded by electroslag welding techniques. Electroslag welding has provided an effective method of coating ship propeller shafts with Monel.RTM. nickel-copper alloys and Inconel.RTM. nickel-chromium alloys. (Monel and Inconel are registered trademarks of the Inco family of companies.) However, as far as known, no one to date has developed a technique for crack free electroslag welding of copper-base alloys such as 70Cu-30Ni. Due to high thermal conductivity and slag removal problems, copper-base alloys are particularly difficult to electroslag weld.
It is an object of this invention to provide a flux useful for electroslag welding of copper-nickel alloys.
It is a further object of this invention to provide an electroslag welding flux useful for both copper-nickel and nickel-chromium alloys.